(19)
(11) EP 0 143 508 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
12.02.1986 Bulletin 1986/07

(43) Date of publication A2:
05.06.1985 Bulletin 1985/23

(21) Application number: 84304911

(22) Date of filing: 18.07.1984
(84) Designated Contracting States:
BE DE FR GB NL SE

(30) Priority: 31.10.1983 US 547304

(71) Applicant: ATLANTIC RICHFIELD COMPANY
 ()

(72) Inventors:
  • Dehm, David C.
     ()
  • Lawson, H. Frank
     ()

   


(54) Additive for water-base drilling fluid and process


(57) An additive for water-base drilling fluid compositions used for drilling subterranean wells is disclosed. In one embodiment, the additive is a sulfonated copolymer of recurring units of a maleimide monomer and recurring units of a vinyl monomer. In another embodiment, the additive is a sulfonated terpolymer of recurring units of a maleimide monomer, recurring units of a vinyl monomer, and recurring units of a carboxyl-containing monomer. Water-base drilling fluids compositions which contain the additive and a process for drilling subterranean wells therewith are also disclosed.





Search report